Upon its first successful submission, a proposal receives a unique code adhering to a standard format. The format of the proposal code is as follows: YYYY.C.NNNNN.Z. Here, “YYYY” denotes the year, “C” identifies the cycle during that year, “NNNNN” is a five-digit running number based on the number of proposals submitted during a given cycle (e.g. 00001 is the first proposal submitted for that cycle) and “Z” denotes the proposal type.
The “C” is used to identify both regular cycles (using a single digit), and DDT cycles (using a single letter). C=1 for the first regular cycle of the considered year, C=2 for the second (if any), etc. C=A for the DDT cycle coinciding with the regular C=1 observation period, C=B for the DDT cycle corresponding to the C=2 observing period, and so on.
The project type identifier can be one of the following: “S” for Regular Proposals, “T” for ToO, “V” for VLBI, “L” for Large, and "P" for Phased Array.
The proposal code is described more fully in the ALMA Proposer's Guide available off the ALMA Science Portal's Documentation and Tools Link.